1. Field of the Invention
The present invention relates to the interconnection of digital communications networks and, more particularly, to a system for automatically connecting a network workstation of a particular protocol type with network equipment of the same protocol type.
2. Background and Prior Art
Rapid changes in digital communications networks have generated a multiplicity of network types, many of which co-exist. For example, many times both host-centric and distributed communications networks are used within a business environment. Each type of network has a useful function necessary in many business environments.
A host-centric communications network is one in which all information transferred between connected devices is managed by a central host processor unit. An example of a host-centric network is one comprising a mainframe from International Business Machines (IBM).RTM. (such as a System/390.RTM.) having a plurality of display terminals (such as IBM 3270 Information Display Systems) connected via a control unit (such as an IBM 3174 terminal controller).
A distributed communications network is one in which information is transferred between devices attached to the network without the intervention of a central host processor. These distributed networks can be constructed from local area network technologies, such as Ethernet (as defined by the IEEE 802.3 standard) or token ring (IEEE 802.5 standard).
The ad hoc development and deployment of the various types of networks in earlier years has resulted in non-compatibility for interconnection. Each network type has its own protocols under which it operates and communicates with other networks of the same protocol type. For instance, a networking protocol may define the manner in which the data is framed or in which errors are checked. Furthermore, a networking protocol normally defines the physical interface, or the actual physical connectivity and medium used by the network. This physical interface definition is analogous to the physical layer of the seven-layer Open Systems Interface (OSI) reference model. Examples are the use of unshielded twisted pair, coaxial or fiber optic cabling for the transmission of bit streams across the particular physical medium. Thus, a business having multiple networks, each of a unique protocol, many times has corresponding sets of wiring in its facility to accommodate them.
Currently, as multiple networks are installed in facilities, the wiring and physical ports compatible with each type of network physical interface also are installed. That is, distinct sets of wiring media are routed throughout the facility to the points where the distinct network workstations (devices/terminals) and network equipment (such as hosts or host control units) are located.
Common practice is to install the various sets of wiring media in a star configuration from a wiring hub or termination point to the network workstations and to the network equipment in a point-to-point manner. This method of wiring also facilitates the management of the networks by providing a central management point as well as resolving the architectural considerations to provide spaces, such as wiring closets, to house electrical wiring panels and communications equipment.
Contemporary installation of wiring media utilizes a single multiprotocol cable that is electrically compatible with several network types. For example, data-grade, shielded-twisted pair wiring is being used to transmit data conforming to the token ring, Ethernet 10baseT, and RS232 serial protocols.
The use of such a multiprotocol medium eliminates the need to wire facilities differently for each unique network. In addition, such a wiring system permits a device, equipped with one of many interfaces, connected to a nearby port wired with the single multiprotocol medium to communicate with the appropriate controller, concentrator, multiplexor, or hub connected at the other end to complete the network connection. Furthermore, the use of such multiprotocol medium permits a device to be moved to another office, for instance, no matter which physical interface the device has if the office has a multiprotocol-wired port.
An example of this is shown in FIG. 1A. The system 10 comprises a wiring closet 12 for providing a centralized location for the network wiring to terminate, and two offices, Office 14 and Office 16, each having a wall port, Wall Port 18 and Wall Port 20. Office 14 has a Terminal Workstation 22 connected to Wall Port 18 while Office 16 has a Token Ring Workstation 24 connected to Wall Port 20.
In Wiring Closet 12, a Patch Panel 26 connects Cabling 28 from Wall Port 18 and Cabling 30 from Wall Port 20 to a Terminal Controller 32 and a Token Ring Multistation Access Unit (MAU) 34 via Cabling 36 and Cabling 38, respectively. Terminal Controller 32 and Token Ring MAU 34 are respectively connected to their corresponding networks via Cabling 40 (to/from Mainframe) and Cabling 42 (to and from token ring network).
In the case where Cabling 28 and Cabling 30 are multiprotocol wiring media, in this case, both supporting the token ring (for Token Ring Workstation 24) and synchronous data link control (SDLC) (for Terminal Workstation 22) physical medium protocols, Token Ring Workstation 24 may be moved to Office 14 and connected to Wall Port 18 as Cabling 28 supports the token ring physical protocol. Likewise, Terminal Workstation 22 may be moved to Office 16 and connected to Wall Port 20. In .order for the network workstations to communicate with their respective networks, however, Cabling 36 and Cabling 38 must be swapped at Patch Panel 26, i.e., Cabling 36 must be disconnected from Patch Panel Port 46 and connected to Patch Panel Port 48 and vice versa with Cabling 38. This process is a manual one and requires that a technician, first, find the cable associated with the newly attached device, then disconnect the cable from its current point of attachment, and finally, reconnect it to a designated port on equipment that is compatible with the device being attached.
Other communications equipment, known as media centers or intelligent hubs (IHUBS), have been devised to replace patch panels in wiring closets so that the networks connected thereto can be remotely managed. Similarly, in this system, the terminals or other devices are connected to wall ports which are attached by various media, including multiprotocol media, to these hubs. Within the IHUBs, modules, or "blades", for each individual protocol type supported (such as token ring or Ethernet networks) are installed. The workstations are connected to these blades. It is possible to remotely reconfigure such an IHUB by means of a network manager so that a workstation of one type, such as a token ring workstation, may be disconnected from its port and reconnected to another port, so long as the other port is connected to a token ring blade within the IHUB. However, a workstation of one type may not be moved to a port configured for another type of workstation. This is shown in FIG. 1B where Terminal Workstation 22 in Office 14 is connected to Terminal Controller Blade 32' in IHUB 50 and Token Ring Workstation 24 in Office 16 is connected to Token Ring Blade 34' in IHUB 50. If Terminal Workstation 22 and Token Ring Workstation 24 were to exchange offices, Terminal Workstation 22 moving to Office 16 and connecting to Wall Port 20 and Token Ring Workstation 24 moving to Office 14 and connecting to Wall Port 18, Cabling 28 and Cabling 30 would have to be manually exchanged. The IHUB 50 is only reconfigurable using Network Manager 52 if the workstations are of the same protocol type and are connected to the same blade or different blades (if an additional bridging blade were available and installed).
Presently, there is no system or method of automatically connecting a network workstation with its corresponding network equipment based upon physical interface protocol of the network. There is a need for such a system as network workstations become more portable as laptop and palmtop personal computers become more prolific in their use. This requirement is shown by the existence of these and other PCs having more than one network interface adapter installed therein.